Recommended .NET Class for a collection of unique integers?

Question

What would you recommend for class that needs to keep a list of unique integers?

I\'m going to want to Add() integers to the collection and also check for existence e.g.

Answer 1

HashSet:

The HashSet class provides high-performance set operations. A set is a collection that contains no duplicate elements, and whose elements are in no particular order...

The capacity of a HashSet object is the number of elements that the object can hold. A HashSet object's capacity automatically increases as elements are added to the object.

The HashSet class is based on the model of mathematical sets and provides high-performance set operations similar to accessing the keys of the Dictionary or Hashtable collections. In simple terms, the HashSet class can be thought of as a Dictionary collection without values.

A HashSet collection is not sorted and cannot contain duplicate elements...